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G. M. WILLIS.

PROCESS FOR THE TREATMENT OF ORES AND MINERALS. T

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1 313,970. Patented Aug. 26, 1919.

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PROCESS FOR THE TREATMENT OF ORES AND MINERALS.

Specification of Letters Patent.

Patented Aug. 26, 1919.

Application filed January 21, 1915. Serial No. 3,429.

To all whom it may concern:

Be it known that I, GEORGE M. Winnie, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Processes for the Treatment of Ores and Minerals, of which the following is a specification.

My invention relates to an improved pro cess for the treatment of ores and minerals by which foreign substances are removed from them or so changed in form by treatment with electric current or gases or both that the metal contained in the orcs or minerals may subsequently be recovered by suitable processes in purer form and more efficiently than has been possible by processes used heretofore. By my process subject the ores or minerals to the flow of current of suitablestrength at a tempera ture insufficient to fuse the same and at the same time supply to the mass of the ore or mineral highly superheated steam and compressed air, which, preferably, are applied alternately to the ore or mineral being treated. If desired, the superheated steam may be used without the compressed air, although under such conditions the results secured are not as efficient.

While I find that the treatment referred to above produces a marked effect upon the ore or mineral treated, I am not aware of the exact nature of the change produced in the ore or mineral, excepting that substances which are contained in the ore or mineral, such as sulfur, phosphorus, etc., are either wholly or partially driven off or so changed as to their molecular arrangement as to be more readily removable in the subsequent treatment so as final product free from these substances, which, if they remained therein, would seriously modify the quality of the metal recovered from the ore or mineral. I also find that by my process minerals which are naturally very refractory are modified as to their characteristics; as, for example, in the case of refractory minerals containing gold the yield of g ld after treatment is much higher than where the mineral is subjected to the same processes of recovery without bein treated by my process.

The sev'era drawings illustrating my invention are as follows:

Figure 1 shows in plan view a furnace to leave the for treating the ores and minerals, and also shows diagrammatically the apparatus and circuit connections employed in connection with said furnace;

Fig. 2 is a vertical sectional view through the furnace shown in Fig. 1;

Fig. 3 is a View taken from the left-hand of the left-hand electrode support contained in the furnace shown 1n Figs. 1 and 2; and

Fig. 4 is a sectional view through the electrodes showing the supports used at the right-hand ends of the same, said view being taken along the line 44 of Fig. 2.

imilar numerals refer to similar parts throughout the several views.

As shown in Figs. 1 and 2, the furnace consists preferably of a metallic casing 10 lined with heat-resistant material 11, which material extends on the four sides of the furnace, and across its bottom, a removable cover 12 of similar construction being provided to close the furnace when in operatlon. The heat-resistant material 11 is preferably made of porous fire clay which may be formed by mixing granulated cork or similar substance with the fireclay before making the lining thereof, as a result of which when the furnace is heated the cork, or similar material, is burned out, leaving air cells throughout the hardened fire clay. Other fire-resistant materials may, of course, be employed instead of the fire clay if desired. In constructing the lining of the furnace it is not necessary that the heat-resisting material shall 'be very highly refractory, for the reason that the temperatures employed in the furnace are not excessive; The heat-resisting lining serves rather as a heatinsulator for the purpose of reventing loss of the heat developed in the urnace.

A gas deliverin device 13 isplaced upon the bottom of the urnace and provided with a supply pipe 14 extending to a superheating coil 15, the other end of which, as indicated in Fig. 1, is connected with a pressure-controlling valve 16 from which a pipe 17 extends to a two-way cook 18 by which connection may be established as desired, either with a boiler 19 through the pipe 20, or through the pipe 21 with a tank 22 con-v taining compressed air. The boiler 19 may be heated by any suitable means, a gas burner 23 being shown in Fig. 1. for accomplishing this result. The supply of gas to the miner 23 ma {a control-led as a sired by a valve 24 located in the pipeconnected with said burner. The swperhea'ting coil 15 is preferably inclosed in a casing 25 to fully utilize the heat hem a gas burner 26 located in the lower portion of said casmg, a'iid the supply of gas to said burner 26 may be controlled as desired by a valve 27 located in the pipe connected with the burner. Suitable apertures may be providedin the casin 25, as indicated, to permit pro er rburnmg of the gas, and the cover 23 of the casing is preferably removable -to permit the assemb ing of the superheatin mechanis The gas delivering mechanism 13 is of a construction similar to that employed in gas bur ers so that the gases delivered In such mechanism to the furnace are wide y and evenly distributed through the material in the furnace, and to prevent the material entering the device 13 a "screen 28 is placed above the said device and extends entirely across the lower portion of the furnace, in which position it is sup orted in any suitable manner by blocks 9 of heat-resistant material The furnace also contains a pluralit of electrodes or current terminals constru d and relatedas follows: At -the lefthand si e of the furnace, as shownin Figs. 1 and 2, ;aplate 30 is disposed, which plate is preferably of iron or steel, and has rigidly secured in it one end of each of the electrodes or terminals 31, the other ends of which are supported by a grid 32 of the gener-al conform'ation indicated in Fig. 4. A second set of electrodes or terminals 33 is disposed between and alternatingwith the electrodes or terminals 31, the right-hand ends ofthese electrodes 38 bein secured in a plate 34 located at the rightand side of the furnace, which plate is similar to the plate 30,;and 'these electrodes or terminals 33 extend through the clearance openings provided in 'the grid 32, and have their lefthand ends supported by a second grid 35 similar to the grid 32, to provide clearance Openings around the electrodes or terminals -31. The grids 32 and 35 are constructed preferably of iron or steel, and to facilitate assembling the electrodes it is preferable that they should be readily removable from the electrodes if desired, and that when in "supporting; osition in engagement with the electrodes t ey may be held in such position by means 'ofset screws 36, as indicated for the id 32 in Fig. 4. The "material of which t e electrodes or terminals is constructed-is immaterial as long as it is a sufficiently @good conductor of electricity to supply electric current to the material to be treated in the furnace. Thus, for example, either carbon or'metal may be employed, and in carrying out my process in practice I find it desirable to construct these electrodes 'Of mild 'stedl or iron, since this material is a sufficiently good conductor of electricity for this lpunpose, and the temperatures employed are not sufliciently high to melt or disintegrate the fircnor Hteel. Furthermore, the electrode construction ma be cheaply and eifectively made by making the electrodes of iron or steel. In this manner the electrode construction may be made sufiiciently stron so that there is no danger of breakage of 51s electrodes or the parts connected therewith by placing the ore or mineral in the furnace and removing the same 'fromthe furnace.

To supply the alternating current to the furnace'the plate 30 is connected by a wire 37 with one terminal of the secondary winding 38 of an alternating current transformer, the other terminal of which winding is connceted by wire 39 with the pivotal oint of a rheostat switch 40, one terminal 0 the resistance 41 of said rheostat beingconnected by wire 42 withthe other plate 34 located in the furnace. The primary winding 43 of the transformer has its terminals connected, as indicated, with a source of alternating current supply 44, which may consist of alternating current feed wires used for distribiition purposes in cities andtowns, or an alternating current generator where such distributing feed wires are not available.

In carrying out my process the ore or mineral is first broken up into a sufficiently divided condition to freely enter between the electrodes 31 and 33, in which condition it is dumped into the "furnace on the screen 28 and in sufficient quantity to practically fill the furnace. he cover of the furnace is then put in place, and by means of the switch 40 alternatlng current is supplied to the electrodes 31 and 33 at a voltage sufiic'ient to cause such an amount of current flow through the ore or mineral as will heat the same after a short'timeto a cherry red heat. As the temperature of the ore or mineral is increased, the amount of voltage impressed upon the electrodes is decreased from "time totime so that when the contents of the furnace have beenheated to the required temperature, which, as referred to, is preferably not above a cherry red heat, but a small quantity of current flow is required'to maintain the heated ore or mineral at that temperature. When substantially the degree of heat of the ore or mineral referred to has been reached, the cook 18 is operated to admit steam from the boiler 19 through the superheating coil 15 to the device 13, the boiler 19 and the superheating coil 15 having previously been placed in operation so as to supply superhe ted steam when the cock is thus operated. he valve 16 is adjusted so that the pressure of the steam delivered to the device 13 is suflicient to 'force thesuperheated steam from the device 13 into the ore or mineral but insufficient to blow the particles of ore or mineral from the furnace.

In practice I find that the pressure required at the device 13 is very low, being not over a fraction of a pound to the square inch, so that there is no need to clamp the cover of the furnace in place to prevent its being lifted by the pressure in the furnace. In practice it is preferable that the cover of the furnace shall fit somewhat loosely upon the furnace so that the gases introduced into the furnace and the gases resulting from the treatment of the ore or mineral may readily escape from the furnace without. however, permitting the escape of an undue amount of heat. The super-heating coil 15, which is preferably of brass or copper, although it may be made of other metal if desired, should at all times be heated sufficiently so that the steam delivered through the pipe 14 to the device 13 is heated sufficicntly hot so that the dry steam produced is dissociated and broken up into its constituent gases, to-wit, hydrogen and oxygen, which gases are delivered to and from the device 13 in this liberated and highly heated condition. This condition of heating of the pipe 15 is attained when the latter is heated to a bright red heat.

After the dissociated steam has been passed through the furnace for a short time, as, for example, from ten to twenty minutes, the cook 18 is moved to a position interrupting the flow of steam from the pipe 20 to the pipe 17 and establishin communication between the pipes 21 and 1 for which condition air is supplied from the tank 22 through the heating coil 15 and delivered to the device 13, and thus to the ore or mineral in the furnace. The interval of this treatment is preferably somewhat shorter than the treatment with the dissociated steam, and then the cook 18 is again moved to its position, interrupting communication be: tween the pipes 21 and 17 and establishing communication between the pipe17 and the boiler 19, and the alternate treatment of the ore or mineral in the furnace with the dissociated steam and ore is continued for a sufficient length of time to remove from the ore or mineral to the desired degree the substances which are attacked by the highly heated gases delivered to the furnace. In practice I find that a treatment of iron ore for a period of three quarters of an hour to an hour will, so far as I am able to deter-- mine by analysis, serve to completely remove from the recovered metal all of the sulfur, phosphorus and impurities contained in the ore originally, although the ore is practically unchanged physically by its treatment in the furnace.

It will be understood-that while I have shown the air tank diagrammatically, this tank in practice will be of a sufficient capacity and provided with suitable charging apparatus in the way of compressors we known in the art to maintain at all times a sufiicient quantity of compressed air in the tank at a proper pressure for delivery to the gas delivering mechanism 13, and that preferably the pressure in the tank should be substantially the same as the pressure generated in the steam boiler, so that the valve 16 may be set in the proper position for any particular material being treated, and remain in that position as long as the same kind of material is under treatment, assuming that the pressures in the boiler and air tank remain substantially constant.

The principal change that is produced in the physical appearance of the ore by the treatment referred to is that the ore is given a finely-powdered condition and is somewhat discolored by the heating, and,

ossibly, by the action of the gases, but as ar as the chemical condition of the ore is concerned the only change produced is the driving off of the sulfur, and other substances, without, however, changin the condition of the metallic portion 0 the ore. For example, in treating iron ore, at the end of the-treatment the ore is still iron oxid, and no metallic iron is produced, for the reason that the tem eratures employed are insufiicient to pro uce any reducing effect.

The temperature to which the ore or mineral is heated varies somewhat with different ores, depending upon the reducing temperature of said ores, it being an important consideration in carrying out in process that the temperature shall not reach the reducing temperature of the ore or mineral. For practical purposes an indication of the roper temperature is had when the ore or mineral is heated to redness, which is attained by heating the ore or mineral to {from 1200 degrees to 1500 degrees Fahren- The ore thus treated is then subjected to a smelting operation of any desired and well known kind for the purpose of reducing the ore to metallic orm, as, for example, by fluxing the ore by means of suitable heat with carbonate of soda, borax, and charcoal, although other fluxes may be employed if desired and other smelting operations employed, depending upon the results desired and the ore being treated.

In the case of iron ore treated as described above, I find that upon subsequently smelting the treated ore in the manner referred to, I secure a quality of iron havin radically diflerent physical and chemioa characteristics from iron produced by any other process of which I am aware. The resultmg iron is, as far as I am able to determine by analysis, chemically pure and extremely ductile and malleable, and, furthermore, of

very di'fl'erentmagnctic properties than iron usually has, for I find upon test that the iron thus produced is 'not highly magnetic.

My process and apparatus are not applicable alone to iron ores, since other ores may be similarly treated when it is desired to free the ores from the presence of substances that may be attacked by the gases delivered to the fiunnace and driven OH in volatilized or oxidized condition. Thus, for-example, I

find that refractory goldsbearing ore when treated in my tfurnace as described above is, in some manner unknown to meychanged, so that the :gold contained in said ore is available and may "be recovered to a much greater degree than is possible without so :treating the ore. Certain tests that I have made in this connection *have shown a recovery of gold from such refractory ore double in amount to that which could be recovered without first so treating the ore.

While my process is particularly adapted to iron ores of various kinds and ores or minerals bearing and containing precious metals, it will be understood that it is equally applicable to any ore or mineral having a composition such that it will not be undesirably changed or transformed by the temperature'ofithe treatment in the fiurnace and from which are or mineral it is desired to remove substances or impurities which may be volatilized, oxidized, or changed in physical orchemical form by ithe gases dehvered to the rfurnace in connection with the action 'of the electric current flowing throughthe furnace. My process and apparatus are further applicable to the partial elimination of impurities by continuing the treatment for only 'a portion of 'thetime required for the complete elimination of said substances, so that as is desirable in some cases a resulting metal may be produced in which the shlfur content, for example, shall not exceed a specified percentage, the advantage of the partial removal of the sulfur in such cases being that the expense of the treatment is reduced.

It will 'be understood that it 'is not necessary in all cases to use the alternating current in carrying out my process, esthe impurities may be removed with a'fair degree of success under certain conditions by heating the material to be treated'in any desired mannor; as, for example,by the application of external heat'to the furnace, or in an equivalent way, and subjecting the material to the action ofthe dissociated steam. This way of carrying out my proeem may be used,- for example, in case itis desired to remove but a part of the substances which may be volatiliced oxidized or changed, and where it is desired to more completely remove these substances, better result may be secured by alternatelytreating the material with the dissociated steam andheated air,\although still maintaining. the teifierature of the material by theappllcatiom .heat in some other way than by the electric current. Where complete and eflfective elimination of said substances is desired, however, this can be most effectively accomplished by maintaining the temperature of the material at the desired point by means of the alternating current flow, as described above, and at the same time alternately treating the ,material with dissociated steam and heated air.

While .I have pointedout above that the temperature durin the treating of the ore or mineral to liminate the undesirable substances is to be maintained below the fusing temperature of the ore or mineral, it is to be understood that rin certain cases where it is desired to secure but a ,partial elimination of these undesirable substances, which may be driven ofl, asabove described, this result may be secured by subjecting the ore or mineral to the action-of the electric current or heated gases, or both, during the heating of the same, where the result of the continued heating is to fuseor melt the ore or mineral, the portion of the heating operation prior to the fusion orimeltingbeing of sufficient duration to eflect the desired amount of elimination before thefusion :onmelting occurs. v

It will also be understood that while the best results are secured by the use of alternating current,,other forms of electric current may be employed in carrying out my process, particularly where the heating ac tion of the current 'isde ended upon to heat the ore or minerajl to t e pro or temperature or to maintain said heate condition.

One of the marked advantages which may be secured by the treatment of ironore having a large phosphorus content so as toeliminate aipart-ofsaid phosphorus is that suffioient of said phosphorusis eliminated by such treatment as to permit of subsequent manufacture of steel bythe Bessemer process for the IPI'OdUCtlQIl ofsteel rails, etc., havmg a Phosphorus content below a specified limiting maximum amount. tilt will readily be appreciated that one of whet-marked ad- Wantagesof treating iron ore by my process so that all of 'the substances which may be removed by vdlatilizing, vaporizing .and changing the same is that the resulting :pure iron isavailable for subsequent treatment by any of the processes well known in 'thelart for the production of high-grade steels having any desired chemical composition to .meetithe varying requirements ofthe=art for such steels.

It will he understood that the electric current may be supplied to the material in the furnace by any desired arrangement of electrodes as long as the electrodes .are in such relation to zthe contents of the'furnace thatthe current 'used will flow through the furnace and the material contained therein, either for the purpose of heating the material contained in the furnace or assisting in the purifying action characterizin my process, or both, as desired. It will a so be understood that I may treat the ores or minerals either with hydrogen or oxygen or both whether said gases are produced by the dissociation of steam or otherwise.

I therefore consider my invention to include broadly the process of treating ores and minerals by electric current or highly heated gases, or both, as described above, .and any form of apparatus that will carry out this process substantially along the line indicated broadly above.

What I claim is:

1. The process of treating ores and minerals, which consists in subjecting them to the action of alternating current flow and alternately passing through the ore or mineral the gases of dissociated steam and air.

2. The process of treating ores and minerals, which consists in subjecting them to the action of alternating current flow and the alternate action of the gases of dissociated steam and highly heated air.

3. The process of treating ores and minerals, which consists in treating them without fusion of the ore or mineral with alternating current flowing through them and alternatel with the gases of dissociated steam an air.

4. The process of treating ores and minerals, which consists in producing an alternating current flow between a plurality of alternating electrodes in the mass of the ore or mineral, and alternately supplying to the ore or mineral the gases of dissociated steam and air.

5. The process of treating ores and minerals, which consists in pro ucin an alternating current flow between a p urality of alternating electrodes in the mass of the ore or mineral without fusion of the ore or mineral, and alternately supplying to the ore or mineral the gases of dissociated steam and air.

6. The process of treating ores and minerals, which consists in sub ecting them to the flow of alternating current, and alternately supplying to them the ases of dissociated steam immediately a ter the dissociation of the same, and highly heated air.

7. The process of treating ores and minerals, consisting in subjecting them to the flow of alternating current through a plurality of paths from electrodes a ternately disposed throughout the ore or mineral, and alternately subjecting the ore or mineral to the action of the gases of dissociated steam immediately after the dissociation of the same, and highly heated air.

8. The process of treating ores, minerals, and similar materials, consisting in heating them to a temperature below their reducing temperature, and subjecting them alternately to the action of the gases of dissociated steam and air.

9. The process of treating ores, minerals, and similar materials, consisting in heating them to a temperature below their reducing temperature, and subjecting them alternatel to the action of the ases of dissociate steam immediately a ter the dissociation of the same and the action of heated air.

10. The process of treating ores and minerals, consisting in subjecting them to the action of electric current flow, and passing through the ore or mineral the gases of dissociated steam and air.

In witness whereof, I hereunto subscribe my name this 12th day of January, A. D. 1915.

GEORGE M. WILLIS.

Witnesses:

ALBERT C. BELL, L. E. HANNEN.

Copies of this patent may be. obtained for five cents each,"b-y addressing the Commissioner of Patents, Wilmington, D. 0. 

